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Message-ID: <3A33AEBE.CB853142@mandrakesoft.com>
Date: Sun, 10 Dec 2000 11:26:38 -0500
From: Jeff Garzik <jgarzik@mandrakesoft.com>
Organization: MandrakeSoft
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To: "Theodore Y. Ts'o" <tytso@MIT.EDU>
CC: Linus Torvalds <torvalds@transmeta.com>, rgooch@ras.ucalgary.ca,
        dhinds@valinux.com, linux-kernel@vger.kernel.org
Subject: Re: Serial cardbus code.... for testing, please.....
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"Theodore Y. Ts'o" wrote:
> 
>    Date: Sat, 09 Dec 2000 11:13:59 -0500
>    From: Jeff Garzik <jgarzik@mandrakesoft.com>
> 
>    > Note how the "rs_interrupt()" routine _tries_ to avoid this by having a
>    > pass counter value, but that logic never triggers because we will loop
>    > forever in receive_chars(), so the rs_interrupt() counter never even gets
>    > to increment.
> 
>    Other places in serial.c check for 0xff, which implies we can and should
>    do the same in the interrupt handler...
> 
> No, other places in the serial driver check for 0xff *after* setting
> various registers and clearing various flags.  Those various
> initializations are critical before you can simply do a "bail if LSR ==
> 0xff" check.

Looking through the code, isn't this setup complete before any
interrupts get delivered to rs_interrupt?


> It's possible (not very likely, but possible) for LSR to go into
> christmas tree mode where all of the flags are set in normal operation.
> So for the interrupt driver, we're going to have to do some kind of loop
> based thing --- if interrupt driver receives 0xff more than some number
> of times, bail.

oh well :)

	Jeff


-- 
Jeff Garzik         |
Building 1024       | These are not the J's you're lookin' for.
MandrakeSoft        | It's an old Jedi mind trick.
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